Burner assembly

ABSTRACT

A burner assembly for a gas turbine is provided. The burner assembly has a combustor, a centrally arranged pilot burner and plurality of main burners surrounding the pilot burner. Each main burner has a cylindrical housing having a lance which is centrally arranged therein and has a fuel channel for liquid fuel. The lance is supported on the housing by swirl blades and an attachment is arranged on the lance in the direction of the combustor. The liquid fuel nozzle is arranged in the attachment downstream of the swirl blades and connected to the fuel channel. For the improved mixing of the fuel with the air, the liquid fuel nozzle is designed as a full jet nozzle and the full jet nozzle has a length and a diameter, the ratio of the length to the diameter is at least 1.5.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the US National Stage of International Application No. PCT/EP2011/061101 filed Jul. 1, 2011 and claims the benefit thereof. The International Application claims the benefits of European application No. 10168107.0 filed Jul. 1, 2010, both of the applications are incorporated by reference herein in their entirety.

FIELD OF THE INVENTION

The present invention relates to a burner assembly for a gas turbine having at least one combustor, wherein the burner assembly comprises a centrally arranged pilot burner and a number of main burners surrounding the pilot burner, wherein each of the main burners comprises a cylindrical housing having a lance which is centrally arranged therein and has a fuel channel for liquid fuel, wherein the lance is supported on the housing by means of swirl blades and an attachment is arranged on the lance in the direction of the combustor, wherein at least one liquid fuel nozzle is arranged in the attachment preferably downstream of the swirl blades and connected to the fuel channel.

BACKGROUND OF THE INVENTION

During operation of the gas turbine compressed air from the compressor is supplied to the combustor. The compressed air is mixed with a fuel, for example oil or gas, and the mixture is combusted in the combustor. The hot combustion gases are finally supplied by way of a combustor output as a working medium to the turbine, where they expand and cool to transmit pulses to the blades, thereby performing work. The vanes here serve to optimize pulse transmission.

In internal combustion engines, particularly those operated using two different fuels, the oil fuel is injected in for example by way of swirl generators, in which the oil is mixed with air. To improve the mixing of oil and air the oil is made to swirl within the nozzles used for injection. Such an oil nozzle is also referred to as a pressure swirl nozzle.

In machines with two different fuels the oil nozzles cannot be arranged in such a manner that the mixing of the fuel with air produces an optimum result in respect of pressure pulsation.

SUMMARY OF THE INVENTION

The object of the present invention is therefore to specify a burner assembly of the type mentioned in the introduction, which resolves the above problem.

According to the invention the object is achieved with a burner assembly of the type mentioned in the introduction in that the at least one liquid fuel nozzle is embodied as a full jet nozzle and the at least one full jet nozzle has a length and diameter, the ratio of the length to the diameter being at least 1.5. The further subclaims contain advantageous embodiments of the invention.

The use of full jet nozzles allows the setting of the fuel profile, in particular of the radial fuel distribution, to be changed very effectively. Full jet nozzles produce a full jet without interfering turbulence. Compared with the pressure swirl nozzle the full jet nozzle has the advantage that a higher preliminary fuel pressure can be converted to a greater penetration depth. With pressure swirl nozzles a higher preliminary pressure causes smaller drops to form, which in turn penetrate less effectively. This means that for greater penetration depth with pressure swirl nozzles a much higher pressure is required than with full jet nozzles. There is therefore no need for expensive pumps for example which can supply a higher preliminary fuel pressure, or pipe systems with high pressure stages, with the full jet nozzle. The full jet nozzle can be embodied as a hole running in the attachment.

The liquid fuel nozzles configured as full jet nozzles inventively have a length to diameter ratio of at least 1.5. According to the invention this provides a liquid fuel jet exiting from the nozzle which mixes optimally with the air swirled by the swirl blades. The length to diameter ratio of at least 1.5 ensures that for example steam bubble formation in the liquid fuel jet is reliably prevented and a sufficiently low turbulence level is maintained in the jet. It also ensures an adequate penetration depth of the fuel jet and good mixing behavior of the jet with the air flowing past. The length to diameter ratio is advantageously selected in a range from 6 to 14. A liquid fuel jet produced by a full jet nozzle with such a length to diameter ratio behaves particularly optimally in respect of penetration depth and mixing properties.

At least one such full jet nozzle can be arranged in the attachment both in the main burners (which can also be referred to as main swirl generators) and also in the pilot burner respectively. The attachment arranged on the lance can be a different component from the lance. However the attachment could also be configured from a number of pieces or as a single piece with the lance.

It is important for the invention to consider the overall concept of the combustion system consisting of a central pilot burner with pilot cone and the main burners arranged around the pilot burner. In principle the penetration depth of the fuel can be varied specifically by adjusting the nozzle diameter, to achieve an advantageous radial fuel profile. Interaction with the central pilot burner also requires optimization of the fuel and drop size distribution, primarily as a function of the relative alignment of the injection position to the pilot cone, in order thus to set the ignition of the fuel/air mixture with an advantageous time delay. This time delay between injection position and fuel combustion is largely responsible for the formation of thermoacoustic feedback, from which combustor pulsations can result.

In addition to the radial fuel profile, the local drop size distributions and air/fuel ratios and also the axial injection position are the main influencing parameters here, which have to be adjusted as a function of local flow conditions of the combustion air. According to the invention therefore the fuel and drop size distribution in the peripheral direction are optimized by means of the appropriately embodied full jet nozzles, to achieve ignition of the fuel/air mixture with an advantageous time delay.

In one advantageous embodiment of the invention provision can be made for the attachment to comprise a central attachment axis and the at least one full jet nozzle to comprise a central axis and the at least one full jet nozzle to be arranged in the attachment in such a manner that the central axis of the at least one full jet nozzle is at an angle of 90 degrees to the central attachment axis of the attachment.

The central axis of the full jet nozzle runs in the longitudinal direction of the full jet nozzle. According to this advantageous embodiment of the invention the fuel is injected essentially perpendicular to the flow direction of the air, thereby achieving a particularly large penetration depth. This allows favorable mixing with the air flowing past.

Provision can advantageously also be made for the attachment to comprise a central attachment axis, the at least one full jet nozzle to comprise a central axis and the at least one full jet nozzle to be arranged in the attachment in such a manner that the central axis of the at least one full jet nozzle is at an angle of between 90+/−30 degrees to the central attachment axis of the attachment.

The angle details relate to the inclination of the central axis in the direction of the central attachment axis. The angle range is selected so that by inclining the central axis of the at least one full jet nozzle it is possible to set a variation of the penetration depth with essentially the same droplet size distribution and fuel injection quantity. This allows the radial fuel profile to be matched in respect of the overall burner assembly, in particular the radial fuel profile of a main burner in respect of the pilot burner.

It can also be considered advantageous for the attachment to have an attachment surface and the at least one full jet nozzle to comprise a central axis, and the at least one full jet nozzle to be arranged in the attachment in such a manner that the central axis of the at least one full jet nozzle is perpendicular to said attachment surface.

The advantageous embodiment of the invention allows injection of the liquid fuel jet perpendicular to the flow direction for a region of the attachment tapering conically to an attachment tip, thereby allowing the greatest possible penetration depth for the fuel for full jet nozzles arranged in this region of the attachment.

It can also be considered advantageous for the attachment to have an attachment surface and the at least one full jet nozzle to comprise a central axis and the at least one full jet nozzle to be arranged in the attachment in such a manner that the central axis of the at least one full jet nozzle forms an angle of −10 degrees to +10 degrees with the surface normal of the attachment surface.

The surface normal runs perpendicular to the attachment surface and is to be considered in each instance in the region of the intersection of central axis and attachment surface. Starting from the surface normal the central axis can run in an inclined manner for this purpose both in the direction of the central attachment axis and in the peripheral direction (azimuthal angle). The specified angle range of −10 degrees to +10 degrees for the inclination of the central axis ensures a large penetration depth for the fuel jet without changing the droplet size distribution or the injected fuel quantity. This allows the fuel profile to be produced around the lance to be set both in the radial and peripheral direction of the lance. This allows the fuel profiles of the individual main burners to be matched to one another in respect of the overall burner assembly.

Provision can advantageously also be made for eight to twelve full jet nozzles to be provided with a diameter for each of the main burners, the diameter being between 0.55 mm and 0.8 mm.

The number from eight to twelve full jet nozzles is preferred. A number from 6 to 16 full jet nozzles per main burner can also be seen as advantageous. A number from 8 to 20 full jet nozzles can also be considered advantageous.

It can also be considered advantageous for full jet nozzles with a diameter between 0.6 mm and 0.7 mm to be provided.

Provision can further be made for full jet nozzles with a diameter between 0.55 mm and 0.65 mm to be provided.

In a further advantageous embodiment of the invention provision can be made for full jet nozzles with a diameter between 0.7 mm and 0.8 mm to be provided.

According to a further advantageous embodiment of the invention provision can be made in at least one of the main burners for full jet nozzles to be arranged along at least one peripheral line running around the attachment.

The peripheral line here does not require a material manifestation but simply serves to describe the arrangement of the full jet nozzles. The at least one peripheral line can run for example in a flat and closed manner around the lance. The peripheral line can for example run in a ring shape and perpendicular to the central attachment axis. By varying the nozzle arrangement and nozzle diameter in the peripheral direction, it is possible to produce fuel profiles that are suitable for suppressing pressure pulsations.

It is important for the invention to consider the overall concept of the combustion system consisting of a central pilot burner with pilot cone and the main burners arranged around the pilot burner. The interaction with the central pilot burner requires optimization of the fuel and drop size distribution primarily as a function of the relative alignment of the injection position to the pilot cone, in order thus to set the ignition of the fuel/air mixture with an advantageous time delay.

It can also be considered advantageous in at least one of the main burners for more full jet nozzles to be arranged on the side of the attachment facing the pilot burner than on the side of the attachment facing away from the pilot burner.

Optimum conditions should be set in particular for the two special instances—injection position in the direction of the pilot flow (which can also be referred to as pilot cone flow) and in the counter direction toward the combustor outer wall. As in the first instance the mixture formation and atomization mechanism produced by powerful shear flows are different from in the second instance, this should be taken into account when setting the fuel profile.

By increasing the number of full jet nozzles in the direction of the pilot burner it is possible to produce a higher fuel concentration in the direction of the pilot burner with the same radial fuel profile and therefore identical penetration depth. This allows the flame position to be set. The inventive embodiment can be realized with one or a number of the main burners, for example with every second of the main burners arranged around the pilot burner.

In a further advantageous development of the invention provision can be made for the number density of the full jet nozzles to vary in the peripheral direction along at least one peripheral line.

According to one exemplary embodiment of the advantageous development of the invention the peripheral line can run in a ring shape and perpendicular to the central attachment axis, with the full jet nozzles arranged along the peripheral line all having the same diameter. According to this exemplary embodiment of the development the number density of the full jet nozzles increases along the peripheral line in the direction of the pilot burner. This allows a higher fuel concentration to be produced in the direction of the pilot burner with the same radial fuel profile.

It can also be considered advantageous for full jet nozzles to be arranged along at least one peripheral line in such a manner that an inclination of the central axes of the full jet nozzles in the direction of the central attachment axis varies in the peripheral direction.

This allows a periphery-based variation of the penetration depth. The angle of inclination in the direction of the central attachment axis can be selected for example between 90+/−20 degrees, with the angle details relating to the angle between the central axis inclined in the direction of the central attachment axis and the central attachment axis. Obtuse setting angles are therefore possible. A periphery-based variation of the penetration depth can be achieved in the cited angle range, regardless of the drop size distribution and the injection quantity.

Provision can advantageously be made for the central axes of the full jet nozzles arranged along the peripheral line to be aligned in an alternating manner, with the central axes alternately running perpendicular to the central attachment axis and being inclined as a maximum 20 degrees from this in the direction of the central attachment axis.

In other words the central axis of every second full jet nozzle runs on the peripheral line perpendicular to the central attachment axis and the central axis of the full jet nozzle arranged in between is inclined in each instance in the direction of the central attachment axis. For example by 10 degrees from the surface normal in the direction of the central attachment axis in the flow direction.

The peripheral line can run for example perpendicular to the central attachment axis in a ring shape around the lance.

Provision can also advantageously be made for full jet nozzles to be arranged along at least one peripheral line in such a manner that the central axis of at least one full jet nozzle has an inclination in the peripheral direction from a position perpendicular to the central attachment axis.

This embodiment of the invention allows an inclination in the peripheral direction (azimuthal angle) as an alternative or in addition to the inclination of the central axis in the direction of the central attachment axis. This allows the interaction of the full fuel jet with the swirl flow to be set in respect of atomization. Isolated adjustment of the drop size distribution can largely be achieved over a limited range here, without producing a substantial change in the radial penetration depth. This azimuthal setting of the central axis of the at least one full jet nozzle can be selected to be the same for example for all the full jet nozzles arranged along the peripheral line. The azimuthal angle of inclination of the central axes could however also be selected for example as a function of the periphery. According to one exemplary embodiment of the advantageous development of the invention the peripheral line runs perpendicular to the central attachment axis in a ring shape around the lance, with the fill jet nozzles having the same diameter along the peripheral line. The central axes of the full jet nozzles run in an alternating manner, with the central axis of every second full jet nozzle running perpendicular to the attachment surface and the central axis of the full jet nozzle arranged in between having an azimuthal angle of 20 degrees to the surface normal.

It can also be considered advantageous for the full jet nozzles to have different diameters along at least one peripheral line.

The different diameters result in different penetration depths for the fuel in the peripheral direction. This allows adjustment of the radial fuel profile of a main burner in respect of the overall burner assembly.

Provision can also advantageously be made for the full jet nozzles to have the same diameter along at least one peripheral line.

In a further advantageous embodiment of the invention provision can be made for the full jet nozzles to be arranged at least along two peripheral lines.

An at least two-row arrangement of the full jet nozzles allows a much larger variation of the fuel profiles than with a single-row arrangement. According to one advantageous development of the invention the at least two peripheral lines run in a ring shape and perpendicular to the central attachment axis around the lance at different axial positions.

An equal or different number of full jet nozzles can be arranged along the two peripheral lines. For example 4 to 10 nozzles can be arranged on each peripheral line. The at least double arrangement of the peripheral lines allows better atomization of the fuel. The arrangement of the full jet nozzles in two axial planes also allows fuel to be distributed in a more regular manner radially at the same peripheral position, by injecting it to different depths into the same flow line of the air flowing past at two axial positions.

It can also be considered advantageous for the full jet nozzles arranged along an upstream peripheral line to have a larger diameter than the full jet nozzles arranged along a downstream peripheral line.

This embodiment of the invention is advantageous when a regular radial distribution is to be achieved.

It can also be considered advantageous for the full jet nozzles arranged along an upstream peripheral line to have a smaller diameter than the full jet nozzles arranged along a downstream peripheral line.

This embodiment of the invention is advantageous when a narrow radial distribution is to be achieved.

Provision can also advantageously be made for full jet nozzles arranged along the downstream peripheral line and full jet nozzles arranged along the upstream peripheral line to be arranged on common flow lines, so that when air flows through the swirl blades, said air can be swirled along the flow lines.

This embodiment of the invention is advantageous in order to achieve a regular radial fuel distribution, when the fuel injected by the downstream full jet nozzles in particular has a smaller or much greater penetration depth than the fuel injected by the upstream full jet nozzles. A smaller penetration depth in particular is considered advantageous. However this embodiment also allows a narrow radial fuel distribution to be achieved, with the fuel injected by the downstream full jet nozzles being injected to the same radial position as the fuel injected by the upstream full jet nozzles. The radial position here is selected in such a manner that the flame stabilizes at a point, the associated time delay of which cannot be initiated in the combustion system.

Provision can advantageously also be made for full jet nozzles arranged along the downstream peripheral line and full jet nozzles arranged along the upstream peripheral line to be arranged so that they are offset from one another in such a manner that when air flows through the swirl blades, said air can be swirled along flow lines on which only one of the full jet nozzles is arranged in each instance.

This embodiment of the invention is particularly advantageous for achieving a regular peripheral distribution of the fuel profile. It can be combined for example with a narrow or regular radial and axial distribution. A regular radial and regular axial distribution in particular is considered advantageous.

Provision can advantageously also be made for full jet nozzles arranged along the downstream peripheral line to inject fuel to the same radial position as full jet nozzles arranged along the upstream peripheral line.

The radial position here is selected in such a manner that the flame stabilizes at a point, the associated time delay of which cannot be initiated in the combustion system.

Provision can advantageously be made for the full jet nozzles to be arranged along at least one helical peripheral line.

In addition to the illustrated periphery-based and axial variations of injection guidance through the full jet nozzles, which allow optimization of the fuel and drop size distribution in the peripheral, axial and radial directions, the time delay spectrum can also be further broadened by the additional helical arrangement of the full jet nozzles.

If injection of the fuel takes place for example along a single helical peripheral line and this peripheral line runs along a flow line of the swirled air flow, a regular radial fuel profile can be achieved with the same full jet nozzle diameters. This embodiment can be advantageous when an alternating periphery-based fuel distribution is required with the greatest possible shift of the time delay spectrum. The arrangement of different full jet nozzle diameters here allows different radial fuel profiles to be set, with regular radial profiles being considered advantageous.

Provision can advantageously be made for the diameters of the full jet nozzles arranged along the at least one helical peripheral line to be configured in such a manner that the diameters increase in the flow direction. This embodiment of the invention is advantageous, when the radial profile is to be homogenized by enrichment of the region close to the axis.

It can also be considered advantageous for the diameters of the full jet nozzles arranged along the at least one helical peripheral line to be configured in such a manner that the diameters increase counter to the flow direction. This embodiment of the invention is advantageous when a narrow radial fuel profile is preferred.

According to a further embodiment of the invention the helical peripheral line may not run along a flow line. This embodiment allows regular periphery-based fuel distribution, it being possible for the diameters of the full jet nozzles arranged along the peripheral line to increase or decrease in the flow direction, depending on the desired radial fuel profile. The angle of inclination of the central axis of the full jet nozzles can also be varied in the flow direction toward the central attachment axis and/or in the peripheral direction along the helical peripheral line, to set the interaction of the swirled flow of air with the full fuel jet in respect of atomization as a function of the nozzle position.

It can also be considered advantageous for the full jet nozzles to be arranged along two helical peripheral lines.

This is advantageous particularly for short attachments, when the greatest possible axial distribution of the nozzle assembly is to be achieved. In addition to a parallel arrangement the double helix can also run anti-parallel, thereby allowing more regular peripheral distributions to be achieved.

According to a further advantageous embodiment of the invention provision is made, for the periphery-based enrichment of the fuel concentration, for the full jet nozzles to be arranged along a helical peripheral line, with the helical peripheral line overlapping to some degree. The diameters of the full jet nozzles here can all be selected to be the same size. The enrichment of the fuel concentration can serve to enrich the shear flow between pilot burner and a main burner.

In one advantageous development of the invention provision can be made for the full jet nozzles arranged along a peripheral line to be at distances from one another and have diameters, such that their sequence is repeated along the peripheral line.

The full jet nozzles arranged along the peripheral line can have regular distances from one another and can all have the same diameter. The distances and/or diameters can however all vary in a regular sequence. This allows additional setting of the radial fuel profile. The radial fuel profile is essential for thermoacoustic stability, as it determines the delay time between injection and combustion. The delay time in turn determines which combustor frequencies can be initiated. According to one exemplary embodiment of the advantageous embodiment of the invention an independent variation of the penetration depth and fuel distribution can be achieved by a sequence of combined full jet nozzle diameters along the peripheral line. For example two different diameters or more can be combined in a regular sequence. By selecting the size ratios of the full jet nozzle diameters it is possible to set the radial region, in which the fuel distribution of the different nozzle diameters is superimposed. The degree of overlap can also be set by selecting the peripheral positions of the full jet nozzles, in particular the mutual distances.

According to one advantageous development of the invention a full jet nozzle with a smaller diameter is arranged along the peripheral line between two full jet nozzles of the same diameter, to produce a fuel profile with a ring-shaped zone of a first fuel distribution and a ring-shaped zone of a second fuel distribution.

According to one exemplary embodiment of the advantageous embodiment 8 to 16 full jet nozzles for example can be provided on the lance. A diameter between 0.5 mm and 0.7 mm can be selected for the smaller full jet nozzles and a diameter between 0.6 mm and 0.8 mm can be selected for the larger full jet nozzles.

According to one advantageous development of the invention the two zones can overlap, for example by arranging the full jet nozzle with the smaller diameter closer to one of the two full jet nozzles with a larger diameter.

It can also be considered advantageous for the full jet nozzles arranged along at least one peripheral line to be configured in such a manner that a fuel injected by means of the nozzles has a radial fuel distribution about the central attachment axis, the fuel distribution comprising a ring-shaped zone of a first fuel distribution and a ring-shaped zone of a second fuel distribution.

The advantageous fuel distribution can be produced by varying the distances, diameters, angles of inclination and/or course of the peripheral line. As already set out above, such a fuel profile can be produced by means of a peripheral line running in a ring shape perpendicular to the central attachment axis, along which full jet nozzles are arranged at equal distances from one another, their diameters alternating between two different sizes.

It can also be considered advantageous for the ring-shaped zone of a first fuel distribution and the ring-shaped zone of a second fuel distribution to overlap.

It can also be considered advantageous for the ring-shaped zone of a first fuel distribution and the ring-shaped zone of a second fuel distribution to be at a distance from one another.

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantages, features and properties of the present invention are described in more detail below based on exemplary embodiments with reference to the accompanying figures. The features of the exemplary embodiments can be advantageous individually or in combination here.

FIG. 1 shows a schematic diagram of a section through a main burner of the inventive burner assembly according to a first exemplary embodiment,

FIG. 2 shows a schematic diagram of a perspective view of a section through the attachment 13 of the exemplary embodiment illustrated in FIG. 1,

FIG. 3 shows a schematic diagram of a section through a main burner of the inventive burner assembly according to a second exemplary embodiment,

FIG. 4 shows a schematic diagram of a section through a main burner of the inventive burner assembly according to a third exemplary embodiment,

FIG. 5 shows a diagram to clarify the exemplary embodiment illustrated in FIG. 4,

FIG. 6 shows a schematic diagram of a section through a main burner of the inventive burner assembly according to a fourth exemplary embodiment,

FIG. 7 shows a cross section through the attachment illustrated in FIG. 6,

FIG. 8 shows a diagram to clarify the exemplary embodiment illustrated in FIG. 6,

FIG. 9 shows a schematic diagram of a section through a main burner of the inventive burner assembly according to a fifth exemplary embodiment,

FIG. 10 shows a schematic diagram of a section through a main burner of the inventive burner assembly according to a sixth exemplary embodiment,

FIG. 11 shows a schematic diagram of a cross section through a radial fuel profile, which can be produced by means of the main burner illustrated in FIG. 10, and

FIG. 12 shows a schematic diagram of a perspective view of an inventive burner assembly.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a detail of an inventive burner assembly in the region of a main burner 107. Swirl blades 17 are arranged around the lance in the housing 12 of the main burner 107. The swirl blades 17 are arranged along the periphery of the lance in the housing 12. The swirl blades 17 direct a compressor air flow 15 into the part of the burner 107 leading to a combustor. The air is made to swirl by the swirl blades 17. The lance also comprises a fuel channel 16. The burner 107 further comprises an attachment 13 on the side leading to a combustor. The attachment 13 can be welded or screwed to the lance for example. The fuel nozzles are preferably arranged downstream of the swirl blades 17 in the attachment 13 and are thus connected for flow purposes to the fuel channel 16, shown here as an oil channel. The inventive burner assembly preferably comprises eight such main burners 107 arranged in a circle (see FIG. 12). The main burners 107 here are arranged around a pilot burner (see FIG. 12) with pilot cone.

Pressure swirl nozzles used hitherto in the prior art exhibit significant pressure pulsations. However major problems then occur in basic load operation. This is now avoided with the aid of the invention.

The plurality of fuel nozzles are therefore embodied as full jet nozzles 1 according to the invention. The embodiment of the nozzle as a full jet nozzle 1, the full jet nozzle size and arrangement allow the penetration depth of the fuel to be set so that an advantageous fuel profile results. The parameters available here are the diameters of the full jet nozzles 1 and the number of full jet nozzles 1. In interaction with the central pilot burner the fuel distribution is set so that ignition of the fuel/air mixture takes place with an advantageous time delay. The time delay between injection and combustion of the fuel is significant for the formation of thermoacoustic feedback loops, from which combustor pulsations can result. The full jet nozzles 1 have a length, the length to diameter ratio being at least 1.5, to achieve thorough mixing. It means that the divergence of the full jet is small enough to prevent drops spinning off in an unwanted manner.

The use of full jet nozzles 1 therefore allows the setting of the fuel profile, in particular of the radial fuel distribution, to be changed very effectively. Compared with a pressure swirl nozzle, the full jet nozzle 1 has the advantage that a higher preliminary fuel pressure can be converted primarily to a greater penetration depth. With the pressure swirl nozzles of the prior art smaller drops are formed due to a higher preliminary pressure and these penetrate less effectively. Therefore a much higher pressure is required for a greater penetration depth with pressure swirl nozzles than with full jet nozzles. There is therefore no need for expensive pumps, which can supply a greater preliminary fuel pressure, or pipe systems with high pressure stages for example with the full jet nozzle 1.

FIG. 2 shows a schematic diagram of a perspective view of a section through the attachment 13. The central attachment axis of the attachment 13 is shown with the reference character 18. The attachment 13 is embodied to taper conically in the direction of the combustor. It comprises a number of full jet nozzles 1, in the present exemplary embodiment four. The full jet nozzles 1 are arranged on the outer periphery of the attachment 13. The central axes of the full jet nozzles 1 are shown with the reference character 19. The central axes 19 of the full jet nozzles 1 are at an angle 20 to the central attachment axis 18 of the attachment 13. The fuel enters the attachment 13 through the fuel channel 16 along the flow direction shown with the reference character 26. The fuel is then injected by the full jet nozzles 1 in direction 25 into the air flow coming from the swirl blades 17. The central axis 19 of the full jet nozzles 1 is arranged essentially perpendicular (90 degrees) to the central attachment axis 18 of the full jet nozzles 1. The central axis 19 of the nozzle 1 can also be perpendicular to the attachment surface. The jet is thus introduced into the air flow in a perpendicular manner, resulting in thorough mixing. An arrangement of 90+/−30 degrees, in particular 90+/−10 degrees, from the central axis 19 of the full jet nozzles 1 to the axis 18 or the attachment surface however also produces a very advantageous assembly.

The attachment 13 comprises a cylindrical part 130 and a part 140 tapering conically in the direction of a combustor. The conical part 140 can have a cone angle of 10 to 20 degrees. This embodiment prevents the flow being fractured at the attachment tip. The full jet nozzles 1 here can be arranged on the conically tapering part 140 of the attachment 13. The position of the full jet nozzles 1 can change as a function of the automatic ignition of the mixture. To achieve a good fuel distribution, eight to twelve full jet nozzles are preferably used (not shown) per attachment 13. Six to sixteen full jet nozzles 1 (not shown) are also advantageous. These are distributed in a regular manner on the periphery of the attachment 13. A good fuel distribution is necessary to comply with emission limits and prevent soot forming. The full jet nozzles 1 can be configured as holes in the attachment 13. A length to diameter ratio of six to fourteen in particular is advantageous in respect of mixing. The length of the full jet nozzle is shown with the reference character 32. The diameter of the full jet nozzle is shown with the reference character 33. The preferred diameter of the full jet nozzles 1 here is 0.55 mm to 0.8 mm but 0.5 mm to 1 mm (not shown) is also advantageous.

Combinations of eight nozzles with a diameter of 0.7 to 0.8 mm or of ten nozzles with 0.6 to 0.7 mm diameter and twelve nozzles with 0.55 mm to 0.65 mm diameter (also not shown) in particular are advantageous.

The full jet nozzles 1 also allow easy adjustment for different thermodynamic conditions, which result for example in a changed air crossflow speed, air density or fuel mass flow, by adjusting the diameters 33 of the full jet nozzles 1 correspondingly.

It is also possible to optimize the design of water components by adjusting the diameter 33 of the full jet nozzles 1. This may be of interest for example, when the emission limits are increased, in particular for NOx. This happens for example in water-poor regions, where gas turbines 1 are also used to produce fresh water.

FIG. 3 shows a detail of the inventive burner assembly in the region of a main burner 107. The main burner 107 comprises a cylindrical housing 12, in which a lance 14 is arranged centrally, being enclosed by a main swirler 10. The schematically illustrated main swirler 10 has swirl blades 17 (not shown), which support the lance 14 on the housing 12. A compressor air flow 15 flows through the main swirler 10 in the direction of the combustor (not shown). The lance 14 extends along a central attachment axis 18, on which an attachment 13 is arranged in the direction of the combustor (not shown). The attachment 13 has a cylindrical part 130 and transitions into a conically tapering part 140 in the direction of the combustor. Present in the conically tapering part 140 of the attachment 13 are full jet nozzles 1 (shown by circles), which are arranged along a peripheral line 11 that runs perpendicular to the central attachment axis 18 and in a ring shape around the central attachment axis 18. In other words the outlets of the full jet nozzles 1 opening toward the attachment surface are arranged along a peripheral line 11 running on the attachment surface, the peripheral line 11 running in the peripheral direction 22 around the attachment 13. Half of the peripheral line 11 is shown in the sectional view. The peripheral direction 22 does not necessarily run perpendicular to the central attachment axis 18. It is only important here that the peripheral line 11 running in a peripheral direction 22 on the attachment surface encircles the central attachment axis 18. The peripheral line 11 illustrated in FIG. 3 does not have to have an actual correspondence but simply serves to describe the full jet nozzle arrangement. According to the illustrated second exemplary embodiment of the inventive burner assembly the number density of the full jet nozzles 1 varies in the peripheral direction 22, as the number density of the full jet nozzles 1 above the central attachment axis 18 is greater than below the central attachment axis 18. To increase the fuel concentration between pilot burner (not shown) and main burner 107, the side of the attachment 13 shown above the central attachment axis 18 faces the pilot burner (not shown). According to the illustrated exemplary embodiment the central axes 19 of the full jet nozzles 1 run perpendicular to the attachment surface. In other words each of the central axes 19 runs in the direction of a surface normal 23. To clarify the concept of surface normals, randomly selected surface normals 23 a, 23 b, 23 c are shown in FIG. 3, the surface normal 23 b being shown in the outlet region of a full jet nozzle 1.

FIG. 4 shows a schematic sectional view of a detail of an inventive burner assembly in the region of a main burner 107 according to a third exemplary embodiment. The structure of the main burner here corresponds to the exemplary embodiment illustrated in FIG. 3 apart from the arrangement of the full jet nozzles 1. According to the third exemplary embodiment these are arranged along a peripheral line 11 running in a ring shape and perpendicular to the main attachment line 18. The inclination of the central axes 19 of the full jet nozzles here runs in an alternating manner along the peripheral line 11. The central axis 19 and therefore also the direction 25 of the fuel jet, in which it leaves the full jet nozzle, run perpendicular to the attachment surface and therefore in the direction of a surface normal 23 in a first full jet nozzle. The central axis 19 of the full jet nozzle 1 following on the peripheral line 11 is inclined 10 degrees from this in the direction of the central attachment axis 18 in the flow direction of the compressor air flow 15. In this sense the inclination of the central axes 19 of the full jet nozzles 1 varies in the peripheral direction 22 along the peripheral line 11. The marked angle φ shows the angle between central axis 19 and attachment surface.

FIG. 5 shows a diagram to clarify the exemplary embodiment illustrated in FIG. 4. By way of example it shows the angle φ between central axis 19 and attachment surface of several full jet nozzles 1 as a function of the peripheral position along the peripheral line 11. The angle φ is referred to as the setting angle.

FIG. 6 shows a schematic sectional view of a main burner 107 according to a fourth exemplary embodiment. The structure of the main burner 07 here corresponds to the exemplary embodiment illustrated in FIG. 3 apart from the arrangement of the full jet nozzles 1. According to the fourth exemplary embodiment the full jet nozzles 1 are arranged along a peripheral line 11 running in a ring shape and perpendicular to the main attachment line 18. The inclination of the central axes 19 of the full jet nozzles here runs in an alternating manner along the peripheral line 11. The central axis 19 and therefore also the direction 25 of the fuel jet, in which it leaves the full jet nozzle 1, run perpendicular to the attachment surface and therefore in the direction of a surface normal 23 in a first full jet nozzle 1. The central axis 19 of the full jet nozzle 1 following on the peripheral line 11 is inclined 20 degrees from this in the peripheral direction 22. The angle of inclination in the peripheral direction 22 can also be referred to as the azimuthal angle.

FIG. 7 shows a cross section through the attachment 13 at the axial height of the peripheral line 11 to clarify the fourth exemplary embodiment illustrated in FIG. 6. The full jet nozzles 1 arranged along the peripheral line 11 are shown by circles. In other words the openings of the full jet nozzles are arranged along the peripheral line 11. The central axes 19 of the full jet nozzles 1 and therefore also the direction 25 of the fuel jet leaving the full jet nozzle run in an alternating manner perpendicular to the attachment surface and are therefore inclined in the direction of a surface normal 23 or 20 degrees from this in the peripheral direction 22. The angle between surface normal 23 and central axis 19 is shown as iv.

FIG. 8 shows a diagram to clarify the fourth exemplary embodiment illustrated in FIG. 6. By way of example it shows the angle between central axis 19 and surface normal 23 in the peripheral direction (azimuthal angle ψ) of several full jet nozzles 1 as a function of the peripheral position along the peripheral line 11.

FIG. 9 shows a schematic sectional view of a main burner 107 according to a fifth exemplary embodiment. The structure of the main burner 107 here corresponds to the exemplary embodiment illustrated in FIG. 3 apart from the arrangement of the full jet nozzles 1. These are arranged along a helical peripheral line 11, the diameter of the full jet nozzles 1 increasing counter to the flow direction of the compressor air flow 15. The air, which is swirled as it flows through the main swirler 10, flows along flow lines 27 along the attachment 13 in the direction of the combustor (not shown). The helical peripheral line 11 here runs in such a manner that the full jet nozzles 1 are arranged on a common flow line 27.

FIG. 10 shows a schematic sectional view of a main burner 107 according to a sixth exemplary embodiment. The structure of the main burner 107 here corresponds to the exemplary embodiment illustrated in FIG. 3 apart from the arrangement of the full jet nozzles 1. These are arranged along a peripheral line 11 running in a ring shape and perpendicular to the central attachment axis, the full jet nozzles 1 having distances from one another and diameters along the peripheral line 11, the sequence of which is repeated along the peripheral line 11. According to the illustrated exemplary embodiment the full jet nozzles 1 are an equal distance from one another, with a full jet nozzle 1 with a smaller diameter arranged between two full jet nozzles 1 of the same diameter. The central axes (not shown) of the full jet nozzles 1 point perpendicular to the central attachment axis 18 in a radial direction.

FIG. 11 shows a fuel profile that can be produced by means of the full jet nozzles 1 illustrated in FIG. 10. The injected fuel here produces a radial fuel distribution around the central attachment axis 18, the fuel channel 16 and the attachment 13, the fuel distribution comprising a ring-shaped zone of a first fuel distribution 28 from the full jet nozzles with large diameter and a ring-shaped zone of a second fuel distribution 29 from the full jet nozzles with small diameter. The fuel distribution from an individual full jet nozzle with large diameter is shown with the reference character 30. The fuel distribution from an individual full jet nozzle with small diameter is shown with the reference character 31. The selected distances between the full jet nozzles 1 and the size ratios of the diameters mean that the ring-shaped zone of a first fuel distribution 28 and the ring-shaped zone of a second fuel distribution 29 overlap.

FIG. 12 shows an inventive burner assembly 108 with a pilot burner 106 with pilot cone 109 and a plurality of main burners 107 arranged around the pilot burner 106. Each of the main burners 107 comprises an essentially cylindrical housing 12, in which a lance is arranged centrally, with an attachment 13 arranged on the lance in the direction of a combustor (not shown). 

1.-36. (canceled)
 37. A burner assembly for a gas turbine, comprising: a combustor; a centrally arranged pilot burner; and a plurality of main burners surrounding the pilot burner, wherein each of the main burners comprises a cylindrical housing having a lance that is centrally arranged therein and has a fuel channel for liquid fuel, wherein the lance is supported on the housing by swirl blades, wherein an attachment is arranged on the lance in a direction of the combustor, wherein a liquid fuel nozzle is arranged in the attachment downstream of the swirl blades and connected to the fuel channel, wherein the liquid fuel nozzle is a full jet nozzle, wherein a ratio of a length to a diameter of the full jet nozzle is at least 1.5, and wherein a fuel and drop size distribution is optimized as a function of an alignment of an injection position of the full jet nozzle relative to a pilot cone.
 38. The burner assembly as claimed in claim 37, wherein the attachment has a cylindrical part and a part tapering conically in the direction of the combustor, and wherein the conical part has a cone angle of 10 to 20 degrees.
 39. The burner assembly as claimed in claim 37, wherein the attachment comprises a central attachment axis, and wherein the full jet nozzle comprises a central axis and is arranged in the attachment so that the central axis of the full jet nozzle is at an angle of 90 degrees or between 90+/−30 degrees to the central attachment axis of the attachment.
 40. The burner assembly as claimed in claim 37, wherein the attachment has an attachment surface, and wherein the full jet nozzle comprises a central axis and is arranged in the attachment so that the central axis of the full jet nozzle is perpendicular to the attachment surface or at an angle of −10 degrees to +10 degrees with a surface normal of the attachment surface.
 41. The burner assembly as claimed in claim 37, wherein the full jet nozzle is arranged along a peripheral line running around the attachment.
 42. The burner assembly as claimed in claim 41, wherein eight to twelve full jet nozzles are provided for the each of the main burners, and wherein diameters of the full jet nozzles are between 0.55 mm and 0.8 mm, or between 0.6 mm and 0.7 mm, or between 0.55 mm and 0.65 mm, or between 0.7 mm and 0.8 mm.
 43. The burner assembly as claimed in claim 42, wherein more full jet nozzles are arranged on a side of the attachment facing the pilot burner than on a side of the attachment facing away from the pilot burner, wherein a density of the full jet nozzles varies in a peripheral direction along the peripheral line, wherein the full jet nozzles are arranged along the peripheral line so that an inclination of central axes of the full jet nozzles in a direction of a central attachment axis of the attachment varies in the peripheral direction, wherein the central axes of the full jet nozzles are alternately aligned running perpendicular to the central attachment axis and is angled maximum 20 degrees in a direction of the central attachment axis, wherein the central axis of at least one full jet nozzle has an inclination in the peripheral direction from a position perpendicular to the central attachment axis.
 44. The burner assembly as claimed in claim 42, wherein the full jet nozzles have different diameters or same diameter along the peripheral line.
 45. The burner assembly as claimed in claim 42, wherein the full jet nozzles are arranged along an upstream peripheral line and a downstream peripheral line running in a ring shape and perpendicular to a central attachment axis of the attachment at different axial positions, wherein the full jet nozzles arranged along the upstream peripheral line have a larger diameter than the full jet nozzles arranged along the downstream peripheral line, or wherein the full jet nozzles arranged along the upstream peripheral line have a smaller diameter than the full jet nozzles arranged along the downstream peripheral line.
 46. The burner assembly as claimed in claim 45, wherein the full jet nozzles arranged along the downstream peripheral line are arranged on common flow lines with the full jet nozzles arranged along the upstream peripheral line so that air can be swirled along the flow lines when the air flows through the swirl blades, or wherein the full jet nozzles arranged along the downstream peripheral line are arranged offset with the full jet nozzles arranged along the upstream peripheral line so that air can be swirled along flow lines on which only one of the full jet nozzles is arranged when the air flows through the swirl blades.
 47. The burner assembly as claimed in claim 45, wherein the full jet nozzles arranged along the downstream peripheral line inject fuel to a same radial position as the full jet nozzles arranged along the upstream peripheral line.
 48. The burner assembly as claimed in claim 42, wherein the full jet nozzles are arranged along a helical peripheral line, wherein diameters of the full jet nozzles arranged along the helical peripheral line increase in a flow direction or increase counter to the flow direction.
 49. The burner assembly as claimed in claim 42, wherein the full jet nozzles are arranged along two helical peripheral lines.
 50. The burner assembly as claimed in claim 42, wherein the full jet nozzles arranged along the peripheral line are at distances from one another and diameters of the full jet nozzles are repeated along the peripheral line.
 51. The burner assembly as claimed in claim 50, wherein a full jet nozzle with a smaller diameter is arranged along the peripheral line between two full jet nozzles of same diameter, wherein the full jet nozzle with the smaller diameter is arranged closer to one of the two full jet nozzles with a larger diameter.
 52. The burner assembly as claimed in claim 50, wherein the full jet nozzles arranged along the peripheral line inject a fuel having a radial distribution about a central attachment axis of the attachment, and wherein the fuel distribution comprises a ring-shaped zone of a first fuel distribution and a ring-shaped zone of a second fuel distribution.
 53. The burner assembly as claimed in claim 52, wherein the ring-shaped zone of the first fuel distribution overlaps with the ring-shaped zone of the second fuel distribution, or wherein the ring-shaped zone of the first fuel distribution is at a distance from the ring-shaped zone of the second fuel distribution. 